UndetVar::dup is not copying the kind field to the duplicated instance

ADDITIONAL SYSTEM INFORMATION :
openjdk version "11" 2018-09-25
OpenJDK Runtime Environment 18.9 (build 11+28)
OpenJDK 64-Bit Server VM 18.9 (build 11+28, mixed mode)

Reproduced both on Linux and MacOSX

A DESCRIPTION OF THE PROBLEM :
Existing code mocking a method with a generic throws declaration using mockito does not compile with the JDK11 Javac.

For a full repro and travis ci build logs, see: https://github.com/danielnorberg/jdk11-behavior-change-repro

REGRESSION : Last worked in version 10.0.2

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile the attached source code with JDK 11 Javac.


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The code successfully compiles.
ACTUAL -
Compilation fails with "unreported exception java.lang.Exception; must be caught or declared to be thrown".

---------- BEGIN SOURCE ----------
import java.io.IOException;

public class Repro {

  /**
   * Compiles on JDK 8, 9 and 10 but fails to compile on JDK 11:
   *
   * unreported exception java.lang.Exception; must be caught or declared to be thrown
   */
  void repro() throws IOException {
    when(f(any()));

    // The below code compiles on JDK 11. Perhaps when() wrapping the call to f(any()) breaks type inference?
    // var v = f(any());
    // when(v);
  }

  interface G<T, E extends Exception> { }

  <T, E extends Exception> T f(G<T, E> g) throws IOException, E {
    return null;
  }

  static <T> T any() {
    return null;
  }

  static <T> void when(T methodCall) {
  }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Rewriting the code as below makes it compile:

var v = f(any());
when(v);

FREQUENCY : always